Side seam for sheet metal containers



May 27, 1941. E. L. HAZARD 2,

SIDE SEAM FOR SHEET METAL CONTAINERS Filed Dec. 7, 1938 Patented May 27, 1941 2,243,628 snon snAM FOR SHEET METAL CONTAINERS Ellison L. Hazard, San Francisco, Calif., assignor to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application December 7, 1938, Serial No. 244,465

1 Claim.

The invention relates to new and useful improvements in a sheet metal container and more particularly to the side seam for the body portion thereof. In the ordinary packers can, the open end of the can body is flanged preparatory to the seaming of the cover end to: the body after the container has been filled. During the handling of the can body by the packer prior to the filling and closing of the same, the solder bond between the overlapping sections at the open end of the can body, and particularly that portion which has been formed into the flange, is sometimes strained to the point of rupturing. This fracturing of the solder bond is likely to extend into the seam to such a distance as to cause a leak when the can is closed by seaming the end thereto.

An object of the present invention is to provide a means for strengthening the side seam in the overlapped section and in the region ofv the flange, which strengthening means is in the nature of a positive mechanical lock for holding the lap sections so firmly in contact as to secure a better solder bond and also to assist the solder bond in resisting strains which are like- 1y to rupture the same.

In the drawing Figure 1 is a plan view of a body blank which is shaped and cut so as to embody the invention; v

Fig. 2 shows a portion of the can body after it has been shaped into cylindrical form, the side edges joined and bumped;

Fig. 3 is a sectional view on the line 3-3 of Fig. 2;

Fig. 4 is a sectional view on the line 4-4, after the side seam has been solder bonded;

Fig. 5 is a View similar to Fig. 3, but showing the seam solder bonded;

Fig. 6 is a view showing in end elevatlon the flanged can body and the position of the interlocked hooks relative to the flange;

Fig. 7 is a sectional view showing the end secured to the flanged can body by double-seaming.

In carrying out the invention a body blank I is formed by cutting. the same from a sheet of metal. The body blank is provided with notches 2, 2 forming a portion 3 which is bent back to provide one of the interlocking hooks of the side seam. The other edge of the blank is cut away at 4, 4 so as to provide a section 5 therebetween which is bent back to form the other interlocking hook. At one end of the hooks the body blank has portions 6 and l which lap one on the other when the hooks are interlocked. At the other end of the side seam are portions 8 and 9 which are overlapped and solder bonded together. As so far described, the side seam is the usual lock and lap seam. The ends of the can body are bent outwardly to form flanges Ill, one at each end of the can body, and to these flanged ends are attached the can end by double-seaming. In Figure 6, the body is indicated at H and the flange formed at the top end thereof at Ill. The side seam is indicated at [2. In Figure 7, the can end I3 is shown as secured to the can body by the double seam indicated at I 4. I

The present invention relates to a mechanical means for strengthening the lap seam in the region between the extreme edge of the flange and the point a or that portion of the side seam which is to be completely rolled into the double seam. In carrying out the invention, the blank is formed with a slit [5 which extends from the end of the blank for a short distance into the blank in a direction parallel with the side edge. The slit then deflects laterally toward the edge of the blank as indicated at I6, and this forms a portion I! which is bent out of the plane of the blank to form the hook. At the opposite side of the blank there is a similar slit 18 which is deflected toward the edge of the blank as indicated at I9, thus forming a portion 20 which is bent in the opposite direction out of the plane of the blank to form a hook. When the blank is formed into the cylindrical body and the hooks 3 and 5 interlocked, then the hooks i l and 20 are also interlocked as shown in Figures 2 and 3. When the side seam is bumped, the hook 20 lies in the plane of the lap section 8, and; the hook I! lies in the plane of the lap section 9, thus forming a very firm interlock between these lap sections right at the end of the blank, which end portion is to form the flange. These interlocked hook portions at the outer edge of the lap sections lie between the edge of the flange and the line a indicated in Figure 6.

The can body with the bottom end double seamed thereto, but without any top end attached, is sent to the packer. The upper end portion of the body, however, is formed with a flange so that the cover or upper end of the can body may be rolled with the flange into a double-seam, as shown in Figure 7. During the handling of the can body as it is conveyed from the manufacturer to the canner, and as it is presented to the filling machine and finally to the seaming ma-' chine, it is often subjected to lateral strains which tend to flatten the open end, and this produces a very severe stress upon the solder bond in the horizontal portions of the flange, often resulting in the rupturing of the solder bond along the edges and when the seaming operation takes place, this rupture continues into the lap sections of the seam until an imperfect joint is produced, resulting in a leak. When, however, the extreme edges of the lap sections are provided with these hooks which produce a mechanical interlock, the lap sections are held so firmly that the solder bond is not ruptured during the severe strain on this open end of the can body incident to the handling of the same. This mechanical interlock prevents the initial rupturing of the solder bond which would continue to a point where the leak would result.

Not only does the mechanical interlock between the edge portions at the flange of the can body strengthen the side seam so that it resists strain during handling, but it also strengthens it so as to resist strains during double-seaming, when the flange is curled with the edge portion of the cover into the double seam indicated at M. Then again, this mechanical interlock between the lap sections, after bumping, will hold said lap sections firmly in contact at the outer edge portions of the lapping sections, while the interlocked books 3 and 5 will hold the lap sections firmly in contact at the inner edge portions of the lap sections. Thus it is that the lap sections are so firmly contacted that the solder willsweat in between and throughout all portions of the lap sections, making a very firm solder bond therefor.

It will also be noted that the cutting of the blank to form the hook 5 is of a slightly diflerent shape at the top or upper end of the can body. The blank is cut along a lineadjacent the hook 5 which is parallel with the edge of the blank throughout substantially one-half the length of the lap section and is then cut away slightly at an angle to facilitate flanging. This increases slightly the extent of lap in the sections at the upper end of the side seam.

While the invention has been described as applied particularly to the upper end of the side seam of a can body which is flanged and subsequently joined to the cover or can end which closes the can, it will be understood that the invention may also be applied to the lap sections at the lower end of the side seam in order to secure a more efiicient solder bonding of the side seam and the joining of the bottom end to the can body. It will also be understood that minor changes in the details of construction and the shaping of the parts may be made without departing from the spirit of the invention as set forth in the appended claim.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is

A sheet metal can comprising a body portion having the edges thereof joined by a side seam including interlocking hooks and lap sections at each end thereof, a solder bond extending throughout the limits of the lock and lap sections, the lap sections at one end of the side seam having similarly formed slits extending into the blank from the top edge thereof to a depth not to exceed the depth of the flange which is to be rolled into a double seam in the attaching of the ends to the body, said slits being disposed relatively to each other and the edges of the lap sections so that a portion of each lap section may be extended through the slit of the other and brought into lapped engagement With each other, thus providing an interlock between the lap sections in the region where the flan e is formed.

ELLISON h HAZARD; 

